(CNN) Suicide bombers from militant group Al Shabaab detonated two vehicles laden with explosives Tuesday near the airport in Mogadishu, Somalia, killing at least 12 people, the UN Assistance Mission in Somalia (UNSOM) said in a statement.

The attack occurred Tuesday morning near the perimeter of Aden Adde International Airport in the Somalian capital, in the vicinity of UN and African Union bases.

Speaking on Radio Andalus, the terror group's propaganda outlet, Al Shabaab spokesman Abdulaziz Abu Musab claimed responsibility for the attack and said the international peacekeeping missions were targeted.

"Al-Shabaab have once again carried out a ruthless attack that has claimed the lives of at least a dozen Somalis," said Michael Keating, the UN Special Representative for Somalia.

"This horrific incident is a fresh example of the extremists' desperate attempts to disrupt political progress. Neither the Somali authorities nor the United Nations will be deterred from moving forward," said Keating.

The U.S. Mission to Somalia expressed "outrage" at the terror act, and called it "yet another demonstration of al-Shabaab's brutality in its efforts to destabilize Somalia."

The terror group has been blamed for attacks in Somalia and neighboring countries targeting international peacekeepers, aid workers and journalists, as well as soft targets such as schools and churches.

Al Shabaab militants killed at least 150 people, most of them students, in a brutal attack on Garissa University College in Kenya in April 2015.

The United States designated Al Shabaab as a foreign terrorist organization in March 2008. The extremist group aims to turn Somalia into a fundamentalist Islamic state.